The present invention relates to a semiconductor member manufacturing method and semiconductor device manufacturing method.
As a substrate for forming a semiconductor device with a high speed and low power consumption, a substrate having a strained silicon layer has received a great deal of attention. When a layer (SiGe layer) made of silicon (Si) and germanium (Ge) is grown on a silicon substrate, and a single-crystal silicon layer is grown on the resultant structure, the silicon layer is strained. Thus, a strained silicon layer is obtained. This strain occurs because the lattice constant of the layer made of silicon and germanium is slightly larger than that of the single-crystal silicon layer.
An SOI substrate having a buried oxide film in a silicon substrate has also received attention and been put into practical use as a substrate for forming a semiconductor device with a high speed and low power consumption.
Also, a technique has been reported, in which a first SiGe layer is formed on a silicon substrate, a second SiGe layer having a higher Ge concentration than the first SiGe layer is formed, and a buried oxide film serving as an insulating layer is formed near the interface between the first and second SiGe layers by SIMOX (Separation by Ion iMplanted OXygen), thereby obtaining a thin SiGe layer with a high Ge concentration on the buried oxide film (xe2x80x9cA Novel Fabrication Technique of Ultra-Thin and Relaxed SiGe Buffer Layers with High Ge Content for Sub-100 nm Strained Silicon-On-Insulator MOSFETsxe2x80x9d, T. Tezuka et al., EXTENDED ABSTRACTS OF THE 2000 INTERNATIONAL CONFERENCE ON SOLID STATE DEVICES AND MATERIALS, Sendai, 2000, pp. 472-473; xe2x80x9cDesign of SiGe/Buried Oxide Layered Structure to Form Highly Strained Si Layer on Insulator for SOI MOSFETsxe2x80x9d, N. Sugiyama et al., EXTENDED ABSTRACTS OF THE 2000 INTERNATIONAL CONFERENCE ON SOLID STATE DEVICES AND MATERIALS, Sendai, 2000, pp. 474-475).
As a characteristic feature of the technique by T. Tezuka et al. and N. Sugiyama et al., SIMOX is used to form a structure with an SiGe layer on an insulating layer. Hence, this technique latently has a technical disadvantage in SIMOX. In SIMOX, a large number of oxygen ions are implanted into a silicon substrate to form a buried oxide film in the silicon substrate. For this reason, in SIMOX, many crystal defects are formed in the silicon substrate, and it is therefore difficult to ensure quality enough to form a minority carrier device. In addition, the oxide film formed in the silicon substrate by SIMOX requires a higher quality. These points are taken into consideration. In the technique reported by T. Tezuka et al. and N. Sugiyama et al., a number of crystal defects (e.g., dislocation) are generated in the SiGe layer by the SIMOX process. Additionally, it is difficult to improve the quality of the buried oxide film. Hence, it is supposed to be difficult to make full use of the latent effects of the strained silicon and SOI structure.
The present invention has been made in consideration of the above situation, and has as its object to provide a new technique for forming a semiconductor member having, e.g., a layer containing silicon and an additive substance on an insulating layer, and a strained silicon layer on the resultant structure.
According to the first aspect of the present invention, there is provided a method of manufacturing a semiconductor member having a layer formed from silicon and an additive material on an insulating layer, comprising a) the preparation step of preparing a first member having a second layer substantially formed from silicon on a first layer containing silicon and the additive material, b) the transfer step of bonding the first and second members via the insulating layer while placing the second layer inside, and transferring the first and second layers from the first member to the second member, and c) the diffusion step of diffusing the additive material contained in the first layer into the second layer. The insulating layer only need be formed at least on the first member side or on the second member side. The insulating layer may be formed on both of the first and second member sides.
According to the preferred embodiment of the present invention, the preparation step comprises the stacking step of forming the second layer on the first layer, the manufacturing method comprises the insulating layer forming step of forming the insulating layer on the second layer of the first member, and the stacking step, insulating layer forming step, and transfer step are executed in an order of the stacking step, insulating layer forming step, and transfer step.
According to the preferred embodiment of the present invention, the first member has a silicon layer under the first layer, and in the transfer step, a portion from the silicon layer to the insulating layer is transferred from the first member to the second member.
According to the preferred embodiment, the diffusion step is executed after the transfer step. In such a method, it is preferable that the method further comprises, after the diffusion step, the growing step of growing a silicon layer on the first layer on the second member.
According to the preferred embodiment, the diffusion step is executed after the insulating layer forming step and before the transfer step.
According to the preferred embodiment, in the insulating layer forming step, the insulating layer is formed by thermal oxidation with annealing at a temperature enough to diffuse the additive material, thereby parallelly executing the insulating layer forming step and diffusion step.
According to the preferred embodiment, in the insulating layer forming step, the insulating layer is formed by thermal oxidation with annealing at a temperature enough to diffuse the additive material, the diffusion step comprises the first and second diffusion steps, the fist diffusion step is executed by annealing in the insulating layer forming step in parallel to the insulating layer forming step, and the second diffusion step is executed after the transfer step. In such a method, it is preferable that the method further comprises, after the second diffusion step, the growing step of growing a silicon layer on the first layer on the second member.
According to the preferred embodiment, the method further comprises, after the transfer step, the thermal oxidation step of thermally oxidizing a surface layer of the second member, and the removal step of removing a thermal oxide film formed on the second member by the thermal oxidation step. In such a method, it is preferable that the method further comprises, after the removal step, the growing step of growing a silicon layer on the second member.
According to the preferred embodiment, it is preferable that the additive material contains germanium.
According to the preferred embodiment, it is preferable that the insulating layer is a silicon oxide film.
According to the preferred embodiment, the first member has a separation layer under the first layer, and in the transfer step, the second member is bonded to the first member having the insulating layer formed by the insulating layer forming step, and then, a member formed by bonding is separated at the separation layer.
According to the preferred embodiment, in the transfer step, a separation layer is formed in the first member having the insulating layer by ion implantation, the second member is bonded to the first member having the separation layer, and then, a member formed by bonding is separated at the separation layer.
According to the preferred embodiment, the first and second layers of the first member are formed by CVD.
According to the preferred embodiment, the first and second layers of the first member are continuously formed in a single CVD step while gradually or stepwise changing a flow rate or concentration of a source gas that supplies the additive material.
According to the preferred embodiment, the first member has the first and second layers on a silicon substrate, and a separation layer at least at one of a portion in the first layer, an interface between the first layer and the silicon substrate, and a portion in the silicon substrate. The separation layer can be, e.g., a porous layer formed by anodizing or an ion-implanted layer.
According to the preferred embodiment, the layer formed from silicon and the additive material is made adjacent to the insulating layer by the diffusion step.
According to the second aspect of the present invention, there is provided a method of manufacturing a semiconductor member having a layer formed from silicon and an additive material on an insulating layer, comprising a) the preparation step of preparing a first member having a second layer substantially formed from silicon on a first layer containing silicon and the additive material, b) the transfer step of bonding the first member and the insulative second member while placing the second layer inside, and transferring the first and second layers from the first member to the second member, and c) the diffusion step of diffusing the additive material contained in the first layer into the second layer.
According to the third aspect of the present invention, there is provided a semiconductor device manufacturing method comprising a) the preparation step of preparing a first member having a second layer substantially formed from silicon on a first layer containing silicon and the additive material, b) the transfer step of bonding the first and second members via the insulating layer while placing the second layer inside, and transferring the first and second layers from the first member to the second member, c) the diffusion step of diffusing the additive material contained in the first layer into the second layer, d) the strained silicon layer forming step of forming a strained silicon layer on the first layer transferred onto the second member, and e) the circuit element forming step of forming a circuit element on the strained silicon layer.
According to the fourth aspect of the present invention, there is provided a semiconductor device manufacturing method comprising a) the preparation step of preparing a first member having a second layer substantially formed from silicon on a first layer containing silicon and the additive material, b) the transfer step of bonding the first member and the insulative second member while placing the second layer inside, and transferring the first and second layers from the first member to the second member, c) the diffusion step of diffusing the additive material contained in the first layer into the second layer, d) the strained silicon layer forming step of forming a strained silicon layer on the first layer transferred onto the second member, and e) the circuit element forming step of forming a circuit element on the strained silicon layer.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.